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Belle calorimeter upgrade

Belle calorimeter upgrade. A.Kuzmin on behalf of sBELLE calorimeter group. Problems with present calorimeter Baseline solution Overview of the ECL parallel session. Problems with the present calorimeter. Calorimeter performance degradation. Baseline. Expected improvement.

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Belle calorimeter upgrade

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  1. Belle calorimeter upgrade A.Kuzmin on behalf of sBELLE calorimeter group • Problems with present calorimeter • Baseline solution • Overview of the ECL parallel session

  2. Problems with the present calorimeter

  3. Calorimeter performance degradation

  4. Baseline

  5. Expected improvement

  6. Pure CsI crystals Pure CsI as compromise of good characteristics, price and possibility to produce in timeRadiation test with gamma – up to 30 krad:Lo change less than 10% for 15kradPure CsI crystals were irradiated by neutrons.Neutron irradiation up to 1012cm-2 did not reveal a degradation within 5%

  7. Photodetector Hamamatsu developed the 2' UVsensitivephototriodes, phototetrodes, photopentods C 10 pF . Dependence of gain factor on voltage is close to linear. Gain factor without magnetic field is 150-250 The gain factor drops down 3.5 times for B=15 kGs About 20-30 %improvement for angle 20-45

  8. Electronics modication

  9. Vladimir Zhulanov, Yury Usov Shaper, FADC, WFA and fast trigger sum on board • Module is being tested • Noise is normal • Linearity is good but dynamical range is limited by power supply • Change +-5V -> 7.5V, 12V ->15V • Diff nonlinearity due to ADC layout (or ADC problem?) • Change tantalum capacitors to ceramic

  10. S. Ryu (SNU) ECL Trigger status Test bench for the trigger sum measurement was prepared Gain Test for Shaper6 bits are reserved for the gainadjustment.

  11. Kenkichi Miyabayashi for Tamaki Hirai / Tomoko Iwashita Recent R&D at Nara • S8664 series APD readout option – Attaching to PureCsI, cosmic signal seen. – Comments on 241Am(60keV X-ray) usage. • Plans of Pr:LuAG – As soon as new ceramic sample gotten, radiation hardness will be tested.

  12. P.P. & APD gain ratio report—4 month testing Test bench to test long term stability of PP and APD was prepared • Ken Chiang, J.Y. Lin, Jeri Chang Both QE and gain factor can be measured

  13. March 2009 2008 2008 2009 PP gain factor stability APD stability More study with photodetector illumination will be carryout

  14. V.Shebalin/A.Kuzmin Calibration/processing of data with new electronics Nakamura san have prepared software to process data with new electronics. The data from new electronics are unpacked from EFC to rawecl chits (cid, dspamp,dsptime, dspag(2bits) rawecl cwaveform (cid, wf(40)) The reconstruction code was modied and data from new electronics are reconstructed to data ECL table. Than the standard procedure of ECL reconstruction is performed. Bhabha data with new electronics have been processe and saved to disk. New electronics allows to suppress pile-up noise Calibration is in progress

  15. B.G. Cheon (Hanyang), H.J.Kim (KNU), E. Won (KU), S.S. Myoung S.K. Kim(SNU), Y.J. Kwon (Yonsei) SNU Review of possibility to usage of different crystals Other possibility for uppgrade - LSO : expensive but others look fine - BSO : decay time 100ns, no mass production - PbWO4 : operation at -25 oC is desired as feasible alternative options Used CsI(Tl) Pure CsI APD or PP An alternative idea Fast Slow • Logic (and probably advantages) • Radiation damage only to front ~10 cm of crystals  need to be checked • High energy signals  enough signal in CsI(Tl) crystals ->do not lose resolution • Fast/Slow  another handle for shower correction by knowing shower shape • Fast trigger signal using fast signal  blind to beam background • Much cheaper

  16. R&D started HYU Power Supply(HV) -1500V Amplifier FADC 400MHz Linux PC PMT (High gain Xp2206) ULS Notice Korea Fedora core 6 CsI (Tl) 20cm CsI (pure) 10cm T.Y.Kim HYU Physics Hybrid signal shape measurement@ sbelle Korea Meeting Page 16

  17. Summary • To keep good performance of the calorimeter at high backgroundconditions we need to upgrade the electronics for the barreland to replace both crystals and electronics in the endcaps . • Pure CsI with pentode readout shows good performance and is baseline option. • The work for barrel electronics upgrade is in progress. New version of the electronics has been developed and being tested. • Trigger modules are developed. Test of the fast shaper trigger output have been performed • Long term performance of the photodetectors have been started • R&D works at NWU and in Korea are going on to search for alternative scintilator and phototodetectors. • Works with the data recorded with new electronics are being continuing. The software for cluster reconstruction has been prepared. • We need in a decision and budget to start the crystal and electronics production.

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